1. FIELD
The subject invention is in the field of instruments used for surveying, navigation and astronomy. More specifically it is in the field of instruments used to aim an antenna at a selected point on the earth's surface toward a selected satellite in geostationary orbit in relation to the earth.
2. PRIOR ART
The United States patents listed here are examples of prior art to the subject invention.
U.S. Pat. Nos. 4,138,826; 4,288,922 and 4,454,658
The devices described in these patents and all other similar devices known to the inventor of the subject invention require, during their use, sources of specific kinds of information such as latitude and longitude of the location of the earth mounted antenna, the declination angle at which to set the instrument, and the data which locates the direction in which a selected satellite lies with respect to the location of the earth mounted satellite. The needs for these kinds of data at the time of use of instruments is inconvenient, may lead to a requirement for a number of instruments to service the area of the earth served by one specific satellite and, in particular, requires more time for each use, adds to the chances for error and requires considerable training and skill in the use of such instruments.
Accordingly, the primary objective of the subject invention is to provide an instrument for accurately aiming antennas in the area served by a satellite toward the antenna on the satellite without need for using supportive data and/or calculations in the process. Other objectives are that the instrument be compact, durable, easy to use and relatively inexpensive to manufacture.